[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 022356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED 02 MAR 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 2N30W EQ50W.  ONLY ISOLATED
THUNDERSTORMS CHARACTERIZE THE ITCZ.

...DISCUSSION...

GULF OF MEXICO...
WEAK SYNOPTIC PATTERN REMAINS IN PLACE OVER THE GLFMEX AHEAD OF
THE NEXT WEATHER SYSTEM CURRENTLY TAKING SHAPE OVER TEXAS AND NW
MEXICO.  AT THE UPPER LEVELS...S STREAM UPPER TROUGH PROGRESSING
ACROSS MEXICO IS PRODUCING BROAD DIFFLUENT FLOW OVER CENTRAL
MEXICO AND THE W GULF.  THIS FEATURE IS EXPECTED TO SLIDE EWD
IGNITING CYCLOGENESIS ALONG A PRE-EXISTING FRONTAL BOUNDARY OVER
THE NW GULF.  THE DEVELOPING LOW IS EXPECTED TO TRACK QUICKLY
EWD OVER THE CENTRAL GULF THURSDAYS TAPPING MOIST SLY FLOW
SETTING THE STAGE FOR THE DEVELOPMENT OF WIDESPREAD
SHOWERS/THUNDERSTORMS INITIALLY OVER THE W AND CENTRAL GULF
TONIGHT THEN PROGRESSING EWD ACROSS THE E GULF AND S FLORIDA THU
NIGHT.  JET DYNAMICS WILL COME INTO PLAY LATE WED AND THU NIGHT
LIKELY MAXIMIZING THE LIFT AND ASSOCIATED SHOWER/THUNDERSTORM
ACTIVITY OVER THE SE GULF AND S FLORIDA AT THAT TIME.  THE
ENTIRE SYSTEM MOVES QUICKLY E OF THE AREA FRIDAY WITH ASSOCIATED
COLD FRONT BRING DRY NLY FLOW IN ITS WAKE.

CARIBBEAN SEA...
BROAD MIDDLE TO UPPER LEVEL RIDGING PREVAILS OVER MOST OF THE
AREA WITH MEAN 500 HPA AXIS EXTENDING FROM CENTRAL AMERICA NEAR
PANAMA/COSTA RICA NEWD ACROSS THE WINDWARD ISLANDS.  WATER VAPOR
IMAGERY INDICATES THE RIDGE HAS BEEN WEAKENING DURING THE DAY AS
THE S EXTENSION OF AN UPPER TROUGH OVER THE W ATLC TRAILS ACROSS
THE AREA FROM HISPANIOLA TO NICARAGUA.  MIDDLE TO UPPER LEVEL
MOISTURE REMAINS LIMITED ACROSS THE AREA PRODUCING DRY/STABLE
CONDITIONS ALOFT. AT THE SURFACE...DISSIPATING STATIONARY FRONT
EXTENDS ACROSS THE W CARIBBEAN FROM THE WINDWARD PASSAGE TO
HONDURAS.  ONLY MINIMAL TEMPERATURE CONTRAST REMAINS ACROSS THE
BOUNDARY BUT IT CONTINUES TO PRODUCE WIDELY SCATTERED SHOWERS
PRIMARILY WITHIN 100 NM TO EITHER SIDE.  A SECOND...EVEN WEAKER
...BOUNDARY HAS PUSHED ACROSS W CUBA BRINGING SLIGHTLY DRIER
AIR WITHIN THE ESTABLISH POST-FRONT PATTERN.  THIS SECOND FRONT
SHOULD CONTINUE TO DISSIPATE OVERNIGHT AS SURFACE HIGH PRESSURE
OVER THE GULF OF MEXICO HAS ALREADY BRIDGED ACROSS THE BOUNDARY
ALLOWING VEERING OF THE WINDS TO THE E AND SE.  ELSEWHERE OVER
THE CENTRAL AND E CARIBBEAN...LOW LEVEL DRY AIR IS PRODUCING A
NOTICEABLE ABSENCE OF CLOUDINESS AND TRADITIONAL TRADE WIND
SHOWERS.  IN FACT...THIS DRY/TRANQUIL PATTERN IS EXPECTED TO
REMAIN IN PLACE THROUGH THE END OF THE WEEK.

ATLANTIC OCEAN...
HIGH AMPLITUDE TROUGH-RIDGE-TROUGH PATTERN PREVAILS OVER THE
SUBTROPICAL ATLC WITH A STRONG AND DEEP LAYERED TROUGH OVER THE
W ATLC WEST OF 50W...AMPLIFYING RIDGE OVER THE CENTRAL ATLC
BETWEEN 30W-50W...AND A DEEP LAYERED LOW OVER THE E ATLC 400 NM
W OF THE CANARY ISLANDS.  THE BULK OF THE ACTIVE WEATHER IS TIED
TO THE W ATLC TROUGH WITH A BAND OF SCATTERED
SHOWERS/THUNDERSTORMS ALONG AND AHEAD OF THE ATTENDANT COLD
FRONT ENTERING THE AREA ALONG 32N55W SWD TO 25N63W.  THE FRONT
CONTINUES SWD AS A WEAKENING BOUNDARY TO THE WINDWARD PASSAGE
WITH WIDELY SCATTERED SHALLOW TOPPED SHOWERS WITHIN 90 NM EITHER
SIDE.  A REINFORCING SURGE/FRONT IS OBSERVED ENTERING THE AREA
JUST E OF BERMUDA ALONG 32N62W SW TO THE S BAHAMAS.
HOWEVER...THIS FEATURE IS DRY WITH ONLY A VERY NARROW BAND OF
LOW CLOUDS NOTED IN SATELLITE IMAGERY.  THE TWO FRONTS ARE
EXPECTED TO MERGE WITHIN THE NEXT 24 HOURS WITH THE MERGED
BOUNDARY THEN PROGRESSING EWD INTO THE CENTRAL ATLC EXTENDING
FROM 32N40W TO 21N60W BY FRI MORNING.  UPPER LEVEL DYNAMICS/LIFT
WILL BE WEAKENING ALONG THE FRONT AS THE SUPPORTING TROUGH LIFT
NWD.  HOWEVER...LOW LEVEL MOISTURE POOLING WILL CONTINUE TO
TRIGGER WIDELY SCATTERED SHOWERS.  OVER THE FAR E ATLC....A 993
MB GALE LOW IS LOCATED APPROXIMATELY 400 NM W OF THE CANARY
ISLANDS NEAR 31N23W. THIS FEATURES CONTINUES TO DRIFT SLOWLY
SEWD WITH ASSOCIATED COLD FRONT ENTERING THE AREA ALONG 31N16W
SWD OVER THE CANARY ISLANDS TO 25N20W 19N30W THEN DISSIPATING
TO 17N45W.  SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 180
NM E OF THE FRONT POLEWARD OF 25N. SCATTERED SHOWERS ARE ALSO
OBSERVED BEHIND THE FRONT WITH THE COLD CORE UPPER LOW N OF 27N
BETWEEN 18W-24W.

$$
RHOME


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